1. Field of the Invention
This invention relates to a motorbike lock, particularly to one having a cylindrical body, two limit discs, two springs, a retainer, a pin, a core, a press button, a sleeve, a cap and a shackle. When the press button fitted in the sleeve is pressed inward to move the core and the retainer to shift inward in a chamber of the cylindrical body, one of the two limit disc is moved to compress the spring in the chamber so that the end of the shackle inserted in a shackle hole of the cylindrical body is stopped by the sidewall of a slot of the retainer and become immovable to let the shackle locked in the condition, and the pin in the retainer inserts in the insert hole of the cylindrical body, with the retainer secured immovable. Thus the lock is locked. In unlocking, a key is inserted through the press button and in the core, and then rotated to rotate the core, with the pin compressed and separating from the insert hole of the cylindrical body so that the retainer may not be restricted by the pin and return to the original position to let the lock unlocked, with the stopper of the shackle on longer stopped by the sidewall of the slot of the retainer.
2. Description of the Prior Art
A conventional motorbike lock shown in FIG. 1 includes a cylindrical body 10, a hollow chamber 100 formed in the cylindrical body 10, a core base 11 placed in a front end of the chamber 100, pin holes 101 and 110 formed respectively in the cylinder body 10, and the core base 11 for pins 13 to insert to combine the core base 11 with the cylindrical body 10. In locking, a first end 120 of a U-shaped shackle 12 is first inserted slantingly in a lock hole 102 of the cylindrical body 10, with a groove 121 of the first end 120 to engage with a stopper 103 in one end of the chamber 100. Then the shackle 12 is pushed to an upright position, letting the second end 122 of the shackle 12 insert in the lock hole 104 of the cylindrical body 10 and locked by the core base 11. Thus the shackle 12 is kept locked, impossible to be pulled out of the cylindrical body 10.
However, the conventional motorbike lock has its first end 120 of the shackle 12 kept immovable with the stopper 103 of the cylindrical body 10, only with one side of the first end 120 contacting with the stopper 103, not locked tightly enough. So a thief may be able to tamper with the shackle 12 or the cylindrical body 10 by striking strongly and break the core base 11 for unlocking, then the lock totally loses its function.